A kinetic study of enzymatic hydrolysis of newspaper with cellulase prepared from Trichoderma viride(IFO30498)has been carried out. The rate of reducing sugar formation decelerated due to inhibition by the products, enzyme thermoinactivation, and substrate inactivation of the enzymes tightly adsorbed on the cellulose surface. The kinetics thake into account the structural complexity of cellulose which can be explanined by the activated substrate coef-ficient, the inhibition by reaction products, and the inactivation of enzyme in the course of the enzymatic hydrolysis. The inactivated enzyme quantity is measured by GFC analysis. The kinetics satisfactorily predict the reducing sugar ac-cumulation from newspaper.